Fasudil prevents calcium oxalate crystal deposit and renal fibrogenesis in glyoxylate-induced nephrolithic mice

N-acetylcysteine regulates oxalate induced injury of renal tubular epithelial cells through CDKN2B/TGF-β/SMAD axis

This study was aimed to investigate the preventive effects of N-acetyl-L-cysteine (NAC) against renal tubular cell injury induced by oxalate and stone formation and further explore the related mechanism. Transcriptome sequencing combined with bioinformatics analysis were performed to identify differentially expressed gene (DEG) and related pathways. HK-2 cells were pretreated with or without antioxidant NAC/with or silencing DEG before exposed to sodium oxalate. Then, the cell viability, oxidative biomarkers of superoxidase dismutase (SOD) and malondialdehyde (MDA), apoptosis and cell cycle were measured through CCK8, ELISA and flow cytometry assay, respectively. Male SD rats were separated into control group, hyperoxaluria (HOx) group, NAC intervention group, and TGF-β/SMAD pathway inhibitor group. After treatment, the structure changes and oxidative stress and CaOx crystals deposition were evaluated in renal tissues by H&E staining, immunohistochemical and Pizzolato method. The expression of TGF-β/SMAD pathway related proteins (TGF-β1, SMAD3 and SMAD7) were determined by Western blot in vivo and in vitro. CDKN2B is a DEG screened by transcriptome sequencing combined with bioinformatics analysis, and verified by qRT-PCR. Sodium oxalate induced declined HK-2 cell viability, in parallel with inhibited cellular oxidative stress and apoptosis. The changes induced by oxalate in HK-2 cells were significantly reversed by NAC treatment or the silencing of CDKN2B. The cell structure damage and CaOx crystals deposition were observed in kidney tissues of HOx group. Meanwhile, the expression levels of SOD and 8-OHdG were detected in kidney tissues of HOx group. The changes induced by oxalate in kidney tissues were significantly reversed by NAC treatment. Besides, expression of SMAD7 was significantly down-regulated, while TGF-β1 and SMAD3 were accumulated induced by oxalate in vitro and in vivo. The expression levels of TGF-β/SMAD pathway related proteins induced by oxalate were reversed by NAC. In conclusion, we found that NAC could play an anti-calculus role by mediating CDKN2B/TGF-β/SMAD axis.

YAP/ACSL4 Pathway-Mediated Ferroptosis Promotes Renal Fibrosis in the Presence of Kidney Stones

The potential association between calcium oxalate stones and renal fibrosis has been extensively investigated; however, the underlying mechanisms remain unclear. Ferroptosis is a novel form of cell death characterized by iron-dependent lipid peroxidation and regulated by acyl coenzyme A synthase long-chain family member 4 (ACSL4). Yes-associated protein (YAP), a transcriptional co-activator in the Hippo pathway, promotes ferroptosis by modulating ACSL4 expression. Nevertheless, the involvement of YAP-ACSL4 axis-mediated ferroptosis in calcium oxalate crystal deposition-induced renal fibrosis and its molecular mechanisms have not been elucidated. In this study, we investigated ACSL4 expression and ferroptosis activation in the kidney tissues of patients with calcium oxalate stones and in mice using single-cell sequencing, transcriptome RNA sequencing, immunohistochemical analysis, and Western blot analysis. In vivo and in vitro experiments demonstrated that inhibiting ferroptosis or ACSL4 mitigated calcium oxalate crystal-induced renal fibrosis. Furthermore, YAP expression was elevated in the kidney tissues of patients with calcium oxalate stones and in calcium oxalate crystal-stimulated human renal tubular epithelial cell lines. Mechanistically, in calcium oxalate crystal-stimulated human renal tubular epithelial cell lines, activated YAP translocated to the nucleus and enhanced ACSL4 expression, consequently inducing cellular ferroptosis. Moreover, YAP silencing suppressed ferroptosis by downregulating ACSL4 expression, thereby attenuating calcium oxalate crystal-induced renal fibrosis. Conclusively, our findings suggest that YAP-ACSL4-mediated ferroptosis represents an important mechanism underlying the induction of renal fibrosis by calcium oxalate crystal deposition. Targeting the YAP-ACSL4 axis and ferroptosis may therefore hold promise as a potential therapeutic approach for preventing renal fibrosis in patients with kidney stones.

Phyllanthus Niruri L. Exerts Protective Effects Against the Calcium Oxalate-Induced Renal Injury via Ellgic Acid

Background: Urolithiasis or kidney stones is a common and frequently occurring renal disease; calcium oxalate (CaOx) crystals are responsible for 80% of urolithiasis cases. Phyllanthus niruri L. (PN) has been used to treat urolithiasis. This study aimed to determine the potential protective effects and molecular mechanism of PN on calcium oxalate-induced renal injury.

Methods: Microarray data sets were generated from the calcium oxalate-induced renal injury model of HK-2 cells and potential disease-related targets were identified. Network pharmacology was employed to identify drug-related targets of PN and construct the active ingredient-target network. Finally, the putative therapeutic targets and active ingredients of PN were verified in vitro and in vivo.

Results: A total of 20 active ingredients in PN, 2,428 drug-related targets, and 127 disease-related targets were identified. According to network pharmacology analysis, HMGCS1, SQLE, and SCD were identified as predicted therapeutic target and ellagic acid (EA) was identified as the active ingredient by molecular docking analysis. The increased expression of SQLE, SCD, and HMGCS1 due to calcium oxalate-induced renal injury in HK-2 cells was found to be significantly inhibited by EA. Immunohistochemical in mice also showed that the levels of SQLE, SCD, and HMGCS1 were remarkably restored after EA treatment.

Conclusion: EA is the active ingredient in PN responsible for its protective effects against CaOx-induced renal injury. SQLE, SCD, and HMGCS1 are putative therapeutic targets of EA.

CID16020046, a GPR55 antagonist, attenuates sepsis‑induced acute kidney injury

Acute kidney injury (AKI) is the most common and serious complication of sepsis, and it is also the main cause of mortality in patients with sepsis. The G protein‑coupled receptor 55 (GPR55) inhibitor CID16020046 was found to suppress the inflammatory response in sepsis models in mice. The aim of the present study was to investigate the effect of CID16020046 on AKI in sepsis mouse models and elucidate the possible underlying mechanisms. A sepsis model in mice was established by cecal ligation/perforation (CLP). The expression levels of GPR55 in the serum of patients with sepsis and the renal tissues of septic mice were determined via reverse transcription‑quantitative PCR and western blot analyses, respectively. The pathological injury of renal tissue was evaluated using H&E and periodic acid‑Schiff staining. ELISA was performed to detect the levels of renal injury‑related factors, including blood urea nitrogen (BUN), creatinine (Cre), kidney injury molecule 1 (KIM1) and neutrophil gelatinase‑associated lipocalin (NGAL) in septic mice. Moreover, the levels of pro‑inflammatory cytokines (TNF‑α, IL‑6 and IL‑1β) were detected via ELISA and western blotting. Apoptosis was determined using TUNEL staining and western blotting. The expression levels of Rho‑associated protein kinase (ROCK) pathway‑related proteins (Ras homolog family member A, ROCK1 and ROCK2) was measured via western blotting. Finally, H&E staining was used to evaluate the effect of CID16020046 on various organs in mice. Compared with the control subjects, the expression level of GPR55 in the serum of patients with sepsis was significantly increased. Compared with the sham group, CID16020046 (20 mg/kg) significantly decreased the levels of BUN and Cre in the serum, as well as the contents of KIM1 and NGAL in the urine. Furthermore, CID16020046 significantly decreased the contents of TNF‑α, IL‑6 and IL‑1β in the serum and renal tissue of septic mice, and reduced cell apoptosis. In addition, CID16020046 effectively suppressed the expression levels of ROCK pathway‑related proteins, and H&E staining revealed that CID16020046 (20 mg/kg) had no toxic effect on the heart, liver, spleen or lung in normal mice. In conclusion, CID16020046 may prove useful for the development of drugs for the treatment of sepsis‑induced AKI.

LncRNA-ATB participates in the regulation of calcium oxalate crystal-induced renal injury by sponging the miR-200 family

Background

LncRNA-ATB is a long noncoding RNA (lncRNA) activated by transforming growth factor β (TGF-β) and it has important biological functions in tumours and nontumour diseases. Meanwhile, TGF-β is the most critical regulatory factor in the process of nephrotic fibrosis and calcium oxalate (CaOx) crystal-induced renal injury. The present study aimed to investigate the biological function and mechanism of lncRNA-ATB in CaOx crystal-induced renal injury.

Methods

The expression level of lncRNA-ATB was detected by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), the expression levels of epithelial-mesenchymal transition (EMT) markers, TGF-β1 and Kidney Injury Molecule-1 (KIM-1) were detected by qRT-PCR, immunofluorescence staining or western blot analysis, cell proliferation was measured with a CCK-8 kit, cell apoptosis was measured by flow cytometry and TUNEL staining, and cell injury was detected with the Cytotoxicity lactate dehydrogenase (LDH) Assay kit and the expression level of KIM-1.

Results

The expression levels of lncRNA-ATB and TGF-β1 were significantly increased in HK-2 cells after coincubation with calcium oxalate monohydrate (COM). COM stimulation caused significant injury in the HK-2 cells, induced cell apoptosis, inhibited cell proliferation, and induced EMT changes. After COM stimulation, the expression levels of the epithelial cell markers E-cadherin and zonula occludens (ZO)-1 in HK-2 cells significantly decreased, whereas the levels of the mesenchymal cell markers N-cadherin, vimentin and α-smooth muscle actin (α-SMA) significantly increased. Interference with lncRNA-ATB expression significantly relieved the COM-induced cell injury, cell apoptosis, proliferation inhibition, and EMT changes. The expression levels of the microRNA-200 (miR-200) family in the HK-2 cells after coincubation with COM were significantly decreased. MiR-200a mimics relieved the COM-induced cell injury, apoptosis, proliferation inhibition, and EMT changes, whereas miR-200a inhibitors abolished the lncRNA-ATB interference-induced relief of the COM-induced cell injury, apoptosis, proliferation inhibition, and EMT.

Conclusion

LncRNA-ATB promoted the COM-induced cell injury, cell apoptosis, proliferation inhibition, and EMT to participate in the process of CaOx crystal-induced renal injury by sponging miR-200s.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00403-2.

LncRNA SPANXA2-OT1 Participates in the Occurrence and Development of EMT in Calcium Oxalate Crystal-Induced Kidney Injury by Adsorbing miR-204 and Up-Regulating Smad5

Objective: To explore the regulatory mechanism of long non-coding RNAs (lncRNAs) in the occurrence and development of epithelial-mesenchymal transition (EMT) in calcium oxalate crystal-induced kidney injury. Materials and Methods: Gene core technique was used to screen differentially expressed lncRNAs and mRNAs in HK-2 cells before and after calcium oxalate monohydrate (COM) stimulation; differentially expressed mRNAs were then analyzed using GO and pathway analysis. The role of target lncRNA in EMT in renal tubular epithelial cells induced by COM was further investigated by applying a series of in vitro experiments. Results: Four differentially expressed lncRNAs (ABCA9-AS1, SPANXA2-OT1, RP11-955H22.1, and RP11-748C4.1) were up-regulated after 48 h of COM stimulation compared to the control group, where up-regulated expression of lncRNA SPANXA2-OT1 was the most significant. Thus, lncRNA SPANXA2-OT1 was further examined. Interference lncRNA SPANXA2-OT1 reversed the down-regulation of E-cadherin and Pan-ck, and up-regulated Vimentin and α-SMA induced by COM stimulation. The application of miR204 inhibitor weakened the interference effect of interfering RNA on lncRNA SPANXA2-OT1 and promoted the occurrence of EMT. Moreover, the miR204 simulator alleviated the overexpression effect of lncRNA SPANXA2-OT1 on COM-stimulated renal tubular epithelial cells and inhibited the occurrence of EMT in renal tubular epithelial cells. Also, a dual-luciferase reporter assay showed that miR-204 could bind to lncRNA SPANXA2-OT1 and Smad5, while lncRNA SPANXA2-OT1 could inhibit cell proliferation and promote cell apoptosis. Conclusion: The lncRNA SPANXA2-OT1 is involved in the occurrence and development of EMT in renal tubular epithelial cells induced by crystalline kidney injury by adsorbing miR-204 and up-regulating Smad5.

Fu-Fang-Jin-Qian-Cao herbal granules protect against the calcium oxalate-induced renal EMT by inhibiting the TGF-β/smad pathway

CONTEXT

Nephrolithiasis is a major public health problem worldwide and Fu-Fang-Jin-Qian-Cao granules (FFJQC) is a traditional Chinese herbal formula that is used to treat nephrolithiasis. The main component of nephrolithiasis is calcium oxalate (CaOx) and the epithelial-mesenchymal transition (EMT) shown to play a crucial role in CaOx-induced kidney injury. However, the mechanism underlying the therapeutic effect of FFJQC on the CaOx-induced renal EMT is unknown.

OBJECTIVE

This study explores the therapeutic benefits and mechanism of FFJQC in oxalate-induced kidney injury.

MATERIALS AND METHODS

60 male C57BL/6 mice were used in this experiment and divided into 6 groups. A mouse kidney stone model was created by intraperitoneal injection of glyoxylate at a dose of 100 mg/kg for 6 days. The standardized FFJQC was used to treat mouse crystal kidney injury by gavage at 1.35 and 2.7 g/kg, respectively. Western blotting and immunostaining for E-cadherin, cytokeratin 18 (CK18), vimentin, smooth muscle α-actin (α-SMA) and transforming growth factor β (TGF-β)/Smad pathway were conducted on renal tissues.

RESULTS

Following CaOx-induced kidney injury, the levels of E-cadherin and CK18 in kidney decreased, while vimentin and α-SMA levels increased. The FFJQC treatment increased the levels of E-cadherin and CK18 and decreased vimentin and α-SMA levels in varying degrees. What's more, the FFJQC reduced the expression of CaOx-induced fibrosis marker collagen II.

CONCLUSION

FFJQC alleviated the CaOx-induced renal EMT and fibrosis by regulating TGF-β/smad pathway. Therefore, the FFJQC is an important traditional Chinese medicine for the treatment of CaOx-induced renal injury and fibrosis.

Nephroprotective Effect of Pleurotus ostreatus and Agaricus bisporus Extracts and Carvedilol on Ethylene Glycol-Induced Urolithiasis: Roles of NF-κB, p53, Bcl-2, Bax and Bak

This study was designed to assess the nephroprotective effects of Pleurotus ostreatus and Agaricus bisporus aqueous extracts and carvedilol on hyperoxaluria-induced urolithiasis and to scrutinize the possible roles of NF-κB, p53, Bcl-2, Bax and Bak. Phytochemical screening and GC-MS analysis of mushrooms’ aqueous extracts were also performed and revealed the presence of multiple antioxidant and anti-inflammatory components. Hyperoxaluria was induced in Wistar rats through the addition of 0.75% (v/v) ethylene glycol in drinking water for nine weeks. The ethylene glycol-administered rats were orally treated with Pleurotus ostreatus and Agaricus bisporus aqueous extracts (100 mg/kg) and carvedilol (30 mg/kg) daily during the last seven weeks. The study showed that Pleurotus ostreatus, Agaricus bisporus and carvedilol all successfully inhibited ethylene glycol-induced histological perturbations and the elevation of serum creatinine, serum urea, serum and urinary uric acid, serum, urinary and kidney oxalate, urine specific gravity, kidney calcium, kidney NF-κB, NF-κB p65, NF-κB p50, p53, Bax and Bak expressions as well as serum TNF-α and IL-1β levels. Moreover, the treatment decreased the reduction in urinary creatinine, urinary urea, ratios of urinary creatinine to serum creatinine and urinary urea to serum urea, Fex Urea and Bcl-2 expression in kidney. In conclusion, although Pleurotus ostreatus and Agaricus bisporus extracts and carvedilol all significantly inhibited the progression of nephrolithiasis and showed nephroprotective effects against ethylene glycol-induced kidney dysfunction, Pleurotus ostreatus and Agaricus bisporus seemed to be more effective than carvedilol. Moreover, the nephroprotective effects may be mediated via affecting NF-κB activation, extrinsic apoptosis and intrinsic apoptosis pathways.

Curcumin ameliorates glyoxylate-induced calcium oxalate deposition and renal injuries in mice

BACKGROUND

Nephrolithiasis is one of the most common and frequent urologic diseases worldwide. Several pathophysiological mechanisms are involved in stone formation, including oxidative stress, inflammation, apoptosis, fibrosis and autophagy. Curcumin, the predominant active component of turmeric, has been shown to have pleiotropic biological and pharmacological properties, such as antioxidant, anti-inflammatory and antifibrotic effects.

PURPOSE

The current study proposed to systematically investigate the protective effects and the underlying mechanisms of curcumin in a calcium oxalate (CaOx) nephrolithiasis mouse model.

METHODS

The animal model was established in male C57BL/6 mice by successive intraperitoneal injection of glyoxylate (100 mg/kg) for 1 week. Curcumin was orally given to mice 7 days before the injection of glyoxylate and for a total of 14 days at 50 mg/kg or 100 mg/kg. Bilateral renal tissue was harvested and processed for oxidative stress index detection, histopathological examinations and other analyses.

RESULTS

Coadministration of curcumin could significantly reduce glyoxylate-induced CaOx deposition and simultaneous tissue injury in mouse kidneys. Meanwhile, curcumin alleviated the oxidative stress response via reducing MDA content and increasing SOD, CAT, GPx, GR and GSH levels in this animal model. Moreover, treatment with curcumin significantly inhibited apoptosis and autophagy induced by hyperoxaluria. Curcumin also attenuated the high expression of IL-6, MCP-1, OPN, CD44, α-SMA, Collagen I and collagen fibril deposition, which were elevated by hyperoxaluria. Furthermore, the results revealed that both the total expression and nuclear accumulation of Nrf2, as well as its main downstream products such as HO-1, NQO1 and UGT, were decreased in the kidneys of mice in the crystal group, while treatment with curcumin could rescue this deterioration.

CONCLUSION

Curcumin could significantly alleviate CaOx crystal deposition in the mouse kidney and the concurrent renal tissue injury. The underlying mechanism involved the combination of antioxidant, anti-apoptotic, inhibiting autophagy, anti-inflammatory, and antifibrotic activity and the ability to decrease expression of OPN and CD44 through the Nrf2 signaling pathway. The pleiotropic antilithic properties, combined with the minimal side effects, make curcumin a good potential choice to prevent and treat new or recurrent nephrolithiasis.

Exploring the Therapeutic Mechanism of Desmodium styracifolium on Oxalate Crystal-Induced Kidney Injuries Using Comprehensive Approaches Based on Proteomics and Network Pharmacology

Purpose: As a Chinese medicinal herb, Desmodium styracifolium (Osb.) Merr (DS) has been applied clinically to alleviate crystal-induced kidney injuries, but its effective components and their specific mechanisms still need further exploration. This research first combined the methods of network pharmacology and proteomics to explore the therapeutic protein targets of DS on oxalate crystal-induced kidney injuries to provide a reference for relevant clinical use.

Methods: Oxalate-induced kidney injury mouse, rat, and HK-2 cell models were established. Proteins differentially expressed between the oxalate and control groups were respectively screened using iTRAQ combined with MALDI-TOF-MS. The common differential proteins of the three models were further analyzed by molecular docking with DS compounds to acquire differential targets. The inverse docking targets of DS were predicted through the platform of PharmMapper. The protein–protein interaction (PPI) relationship between the inverse docking targets and the differential proteins was established by STRING. Potential targets were further validated by western blot based on a mouse model with DS treatment. The effects of constituent compounds, including luteolin, apigenin, and genistein, were investigated based on an oxalate-stimulated HK-2 cell model.

Results: Thirty-six common differentially expressed proteins were identified by proteomic analysis. According to previous research, the 3D structures of 15 major constituents of DS were acquired. Nineteen differential targets, including cathepsin D (CTSD), were found using molecular docking, and the component-differential target network was established. Inverse-docking targets including p38 MAPK and CDK-2 were found, and the network of component-reverse docking target was established. Through PPI analysis, 17 inverse-docking targets were linked to differential proteins. The combined network of component-inverse docking target-differential proteins was then constructed. The expressions of CTSD, p-p38 MAPK, and p-CDK-2 were shown to be increased in the oxalate group and decreased in kidney tissue by the DS treatment. Luteolin, apigenin, and genistein could protect oxalate-stimulated tubular cells as active components of DS.

Conclusion: The potential targets including the CTSD, p38 MAPK, and CDK2 of DS in oxalate-induced kidney injuries and the active components (luteolin, apigenin, and genistein) of DS were successfully identified in this study by combining proteomics analysis, network pharmacology prediction, and experimental validation.

The influence of fasudil on renal proximal tubular cell epithelial-mesenchymal transition induced by parathormone

BACKGROUND

Renal fibrosis is a common pathway through which a variety of chronic kidney diseases progress to end-stage renal disease. Epithelial-mesenchymal transition (EMT) of renal proximal tubular cells is one of the most important factors in renal fibrosis. This study investigates if fasudil could influence EMT of renal proximal tubular cells.

METHODS

HK-2 cells in passage 3-4 were used for all experiments. The cells were divided into five groups and treated with different concentrations of PTH and then observe cellular morphological changes at 0, 24 and 48 h using an inverted microscope and investigate the expression of the epithelial cell marker E-cadherin and the renal fibroblast marker α-smooth muscle actin (α-SMA).

RESULTS

PTH significantly induced EMT, fasudil-inhibited EMT induced by PTH to different degrees, and the inhibitory effect of fasudil was most pronounced at 20 μmol/L.

CONCLUSION

Monitoring PTH levels, early prevention and control of hyperparathyroidism and reducing the concentration of PTH are important means to improve prognosis and delay the progression of chronic kidney disease. Fasudil can restrain EMT induced by PTH; this conclusion provides experimental data for the application of fasudil in the clinical prevention and treatment of renal fibrosis.

Long non-coding RNA CHCHD4P4 promotes epithelial-mesenchymal transition and inhibits cell proliferation in calcium oxalate-induced kidney damage

Kidney stone disease is a major cause of chronic renal insufficiency. The role of long non-coding RNAs (lncRNAs) in calcium oxalate-induced kidney damage is unclear. Therefore, we aimed to explore the roles of lncRNAs in glyoxylate-exposed and healthy mouse kidneys using microarray technology and bioinformatics analyses. A total 376 mouse lncRNAs were differentially expressed between the two groups. Using BLAST, 15 lncRNA homologs, including AU015836 and CHCHD4P4, were identified in mice and humans. The AU015836 expression in mice exposed to glyoxylate and the CHCHD4P4 expression in human proximal tubular epithelial (HK-2) cells exposed to calcium oxalate monohydrate were analyzed, and both lncRNAs were found to be upregulated in response to calcium oxalate. To further evaluate the effects of CHCHD4P4 on the cell behavior, we constructed stable CHCHD4P4-overexpressing and CHCHD4P4-knockdown HK-2 cells. The results showed that CHCHD4P4 inhibited cell proliferation and promoted the epithelial-mesenchymal transition in kidney damage and fibrosis caused by calcium oxalate crystallization and deposition. The silencing of CHCHD4P4 reduced the kidney damage and fibrosis and may thus be a potential molecular target for the treatment of kidney stones.